Tiiorsten nordenfelt



(No Model.) y 2 Smets-sheenl 1,

T. NORDENPELT 81; C. GVMIDDELBOB y A NAVAL RANGB-HNDBR.

110,414,819.V 881611181 Nov. 12,1889.

N. PUERS, Pholurmgnpher. wnmingmn. n.12.

(No Model.) 2 Sheets-Sheet 2.

T. l1\IORDE1\TF11L'1' 8v C. G. MIDDELBOB.

NAVALRANGB FINDER.

No. 414,819. Patented Nov. 12, 1889.

UNITED STATES PATENT GEEICE.

TllORSTlN NORDENFEL'F, OF VESTMINSTER, ENGLAND, AND CHRISTIAN GJORTZ MIDDELBOE, OF COPENHAGEN, DENMARK.

NAVAL RANGE-FINDER.

SPECIFICATION forming part of Letters Patent No. 414,819, dated November 12, 1889.

Application filed February 7,1887. Serial No. 226,751. (No model.) Patented in England December 5, 1884, No. 16,029, and August 15, 1885, No. 9,672; in France August 8,1885, No. 170,588, and September 15, 1886, No. 176,161; in Italy September 3 0, 1885, No, 18,849, and June 80, 1.886, No. 19,969 in Spain December Z2, 1885, No. 7,866, and August 21,1886,

No. 9,218, and in Germany May 16, 1886, No. 38,910.

To a/ZZ whom, t may concern.- Be it known that we, THoRsTEN NORDEN- FELT, civil engineer, a subject ot the King ot' Sweden, residing at 58 Parliament street, in the city of Westminster, England, and CHRISTIAN GJoETZ MIDDELBOE, a subject of the King of Denmark, lieutenant in the royal Danish navy, of Copenhagen, in the Kingdom of Denmark, jointly have invented certain ro new Vand useful Improvements in Naval Range-Fimlers, (for which we have received Letters Patent in Great Britain, No. 16,029, dated December 5, 1884, and No, 9,672, dated August 15,1885; in France, No. 170,538, dated August 8, 1885, and No. 176,161, dated September 15, 1886; in Italy, No. 18,849, dated September 80, 1885, and No. 19,969, dated June 30, 1886; in Spain, No. 7,866, dated December 22, 1885, and No. 9,218, dated August 21, 1886, and in Germany, No. 38,910, dated May 16, 1886,) of which the following is a specification.

This invention has for its object improvements in instruments for measuring distances 2 5 at sea. Ve make these instruments to indicate conveniently and directly and without the aid of calculations or tables the distance of a ship or other object at sea.

The main principle upon which the instruments are constructed is that for any given height above the sea-level the angle between the .line from the eye t0 the horizon and the perpendicular lowered from the eye to the sea-level is known, (it is constant and differs 3 5 but slightly from a rectangle,) and if the angle between the line from the eye to the horizon and the line from the eye to the waterline of a ship or other object can be measured, then inthe rectangular triangle determined'by the following three points: First,

the eye of the observer; second, the point on.

the water-line the distance of which is to be measured, and, third, the base of the perpendicular lowered from the observers eye to the sea-level. Two angles and one side are known; therefore any other element of the triangle can be calculated.

We provide our instruments with a scale by which the necessity of calculation is avoided.

5o This scale shows the distances resulting from ping the other.

varying angles between the line from the eye to the horizon and the line from the eye to the object when the heightof the eye is known. The operator measures this angle, and an index directly indicates the distance on the scale.

The instrument is represented by the annexed drawings.

Figure 1 is a plan view of the complete instrument. Fig. 2 is an end view of one of the 6o telesopes with the eye-piece end unscrewed and removed. Fig. 8 is a section taken just behind parts ff2 of Fig-. 2. Fig. 4 is a view showing features represented by Fig. 2, as seen when looked at from the opposite direction. Fig. 5 is a diagram showing the arrangement of the lenses. Fig. 6 is a central crosssection through one of the telescopes, showing also the milled wheel in plan. Fig. 7 isa front view of the lens-sections as they appear 7o when coinciding. Fig. 8 isa front View ot the lens-sections separated, and Fig. 9 is a cross-section on the line 9 9 of Fig. 7.

The instrument here represented is a binocular telescope. In each telescope one of the lenses is divided into two' parts, and one part is movable in respect to the other. Nhen the two parts occupy their natural position, or, in other words, when the two parts are \conc'entric or coincide, as shown in Fig. 7, 8o

the telescope presents a single image; but when the two parts of the divided lens are not concentric, (one part being raised above the other, as shown in Fig. 8,) then the instrument presents two images, one overlap- By moving the half-lens a suitable distance the horizon-line in one image can be brought to coincide with the waterline of a oating body, as seen in the other image. 9o

The instrument is provided with a scale on which the distance between the centers of the y two half-lenses is measured, and this scale is so marked that when the instrument is set as above described the distance from the observer of the oating body upon which the instrument has been set can be'directly read o. The scale being graduated to correspond with the distance, it is necessary to move the halt-lens to bring the horizon-line roo of one image to coincide with the water-line of the other image for all distances.

The instrument consists of two parallel telescopes a a, connected in any suitable way, so that the distance between the telescopes may be adjusted to suit the eyes el the observer while maintaining their parallelism, as usual. The telescopes also have the usual arrangements for focusing, there being a draw-tube C, and the draw-tubes are moved in and out simultaneously in the usual way. The two telescopes are similarin all respects. Beyond the teens ot' the objectglass (l and lens c there is a convex lens carried by the draw-tube and divided diametrically on the line f inte two equal parts or segments f and (See Figs. '7, S, and 9.) One half er part is iixed and the other half is in slidingl contact therewith, being mounted in a slide g, Fig. 52, which is movable in a plane at right angles tothe axis of the telescope between plate-sections g gf, so that the two halves j" f2 of the lens remain always in contact, though the part fgis capable of sliding laterally in the vertical plane of the lens. The slide has a projection y', carrying a pin g2, which projects through a slot. g5 and which engages with a snailgroove g3 in the face of a disk gt A frietion-block g8, mounted on the end of a spring gf and secured to the slide g at gl, bears against the inner face of the tube and prevents the slide r/ from moving except when positively actuated. The drawtube c is continued through the center of the disk g4, as shown in Fig. (5, and is then bent back parallel with the disk g and provided with an annular rim or flange c', to the end of which the eye-piece is secured.

The disks g of the two telescopes can be turned simultaneously by means of a milled head 7i, secured midway the length of an axis h', provided at its ends with worms 7a2, engaging with corresponding teeth 7L on the backs of the disks. vOn the periphery oi' each disk is a flange z', and on this are the graduations, as shown in Figs. l and (i. The flange moves relatively to a pointer y'.

7e and k2 are the lenses of the eye-piece.

The graduations are such that when the water-line of the floating body is brought to the horizon the true distance is read. The scale is of course graduated for a given elevation-say :titty feet. It the instrument is set on an elevation of one hundred feet, a proper allowance is of course made for this change.

Uien the sections f' f2 of the lens coincide, as shown in Fig. 7, but one image is seen.

After adjusting the instrument, as shown in Fig. S, two images are seen7 one above the other, the horizondine of one image being brought te coincide with the water-line of the floating body, as seen in the other image. The scale'iiange 'L' moves correspondingly with the movable lens, and the amount of movement of the scale relatively to the pointer j is indicated, the scale being so marked that the distance from the observer to the object maybe directly ascertained, the distance which the scale-flange nieves depending en the movement of the lens, which depends on the distance of the object.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim, is-

l. The combination of a telescope, the meas tiring-lens diametrically divided into two part-s er sections, a slide in which one of the lens-sections is carried, mechanism, substantially such as described, for operating the slide to adjust the movable lens-section relatively to the other along the line of division and in the vertical plane ot` the lens-sections, and a scale graduated to show the distance of the object to which the instrument is set from the object en which the instrument is mounted.

2. The combination of the telescope, the measuring-lei is diam etrically divided into two parts or sections, a slide in which one ot' the lens-sections is carried, a scale connected with the slide, an adjusting device hier moving the slide and correspondingly moving the scale, whereby the vertical adjustment of the movable lens-section and the correspending adjustment of the scale indicate the distance of the object to which the instrument is set from the object on which the instrument is mounted, substantially in the manner hereinbefore set forth.

In a binocular telescope, the combina tion el two measuring-lens sections in each telescope, a slide in each telescope for each movable lens-section, an operating or adjusting device h, connections between the adjusting device and the slides, whereby they may be simultaneously moved to adjust the measuring-lens sections relatively to the stationary sections along theline of division and in the vertical plane et the lenses, a scale graduated to show the distance of the ob ject to which the instrument is set from t-he object on which the instrument is mounted.

4. The combination of the telescope7 the divided leus, the slide carrying one part et' the lens, a pin connected with the slide, a toothed graduated disk havingasnail-groove with which the pin engages, and the worin engaging the teeth of the graduated disk, substantially as and for the purpose setforth.

THORSTEN NOltDENFlll/l, CHRISTIAN GJORTZ BIIUDELBOI'I. Witnessess to the signature of Thorsten Nordenielt:

E. BRUsEwrrZ, F. A. NOL, Both of 53 Parliament Street,

IIO

lVitnesses to the signature ot' Christian Gjortz Middelboe:

L. lloran, Deljingade i), Copenhagen.

JOH GRNDTOIG, I)1'cimzfngcnsgade, No. l, @optelling/(Jn. 

